Microwave oven



FIG. 1 is a perspective view of a microwave oven, showing our new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a plan view thereof;

FIG. 4 is a bottom view thereof;

FIG. 5 is a rear elevational view thereof;

FIG. 6 is a right side elevational view thereof; and

FIG. 7 is a left side elevational view thereof. 

The ornamental design for a microwave oven, as shown and described. 